Effects of Preservatives Used in the Cosmetics Sector

Effects of Commonly Used Preservatives in the Cosmetics Sector Our skin is the largest organ in our body. It serves as a protective barrier against external influences and helps control thermal regulation, infection and more. Our skin reacts to the environment and can adapt, and this includes the cosmetic products we use on our skin. Skin has an optimal pH level between 4.0 and 6.5. pH level refers to the acidity or alkalinity of an environment. Many microorganisms (such as bacteria, fungi, yeast) cannot survive in an environment where the pH level is below 4 or above 10, but they thrive in an environment similar to our skin's pH. While we could design products at the extreme ends of the pH scale to prevent microorganism growth, such products would likely irritate or damage our skin. Therefore, we need preservatives to create an inhospitable environment for microorganisms while maintaining an optimal pH level for our skin health. In general, a preservative should have a broad spectrum, such as sufficient solubility in water and activity independent of pH. The most common antimicrobial preservatives are divided into several groups based on their chemical structure and functional groups: organic acids, alcohols, phenols, aldehydes and formaldehyde donors, isothiazolinones, biguanides, quaternary ammonium compounds, nitrogen compounds, heavy metal derivatives and inorganic compounds. Each of these preservative groups has a different mode of action and activity spectrum under correct concentration and formulation properties. The use of certain preservatives may be limited or concentrations may be restricted depending on product type and application area. As mentioned above, preservatives are typically used to protect cosmetic products from microbial degradation. However, if we consider the issue from a different angle, evidence has been observed that some preservatives may increase oxidation in O/W emulsions. This can have disadvantages for product quality, efficacy and consumer health and well-being. Therefore, the effect of preservatives on oxidation should also be examined. People are exposed daily to a wide variety of chemicals that occur naturally in most environments, but others are derived from human activities found in food, water and various daily cosmetic and hygiene products. Preservatives used to ensure product shelf life are among them. However, there are concerns regarding the use of preservatives in cosmetics. Many preservatives used as antibacterial agents have been linked to numerous human health problems. Exposure occurs primarily through the skin. Children exposed to preservative compounds at an early age have higher rates of developing allergies, asthma and eczema. Human skin serves as the first line of defense against infectious and toxic external agents and is rich in various microorganisms called microbiota, including bacteria, viruses, yeast, fungi and archaea. In recent years, it has been reported that the skin microbiome plays an important role in human health. In addition to innate human immunity, the large population of microorganisms living on the skin forms a skin barrier that keeps the skin healthy. When the balance of skin microbiota is disrupted, there is a change in the diversity and population of the microbiota. In these cases, the individual's skin becomes more sensitive to the effects of external agents and the frequency of various skin diseases increases. In fact, the preservatives we use antimicrobially to protect cosmetic products not only kill harmful bacteria on the skin but also harm beneficial bacteria, damaging the balanced microbiota. As a result, skin diseases such as irritation, eczema and allergies develop on the skin. Recent research has found that some raw materials used as preservatives affect thyroid hormone metabolism and are potential endocrine disruptors, in addition to skin diseases and allergic reactions. An organic compound used both as a preservative and for acne has recently been added to the list of endocrine disruptors. Some preservative raw materials have even been detected in breast milk samples and urine at high concentrations. This shows that exposure is not limited to skin and respiratory routes but also affects the circulatory system. Despite all this, it has been observed that some compounds used as preservatives have carcinogenic, neurotoxic potential and the ability to harm reproductive organs and the ocular surface. These preservatives used in cosmetics not only affect humans but also harm the environment and marine life. Some of the preservatives that enter groundwater and seas show toxic effects on organisms living in water. The number of fish in the Marmara Sea has declined from around 120 to around 10 within 15 years. The use of preservatives showing toxic effects on marine life is not a small factor in this decline. The human pursuit of beauty began thousands of years ago. Today it continues with unending passion. Cosmetic manufacturers should be encouraged to use preservatives that comply with green chemistry, have increased efficacy, adjusted dosage ratios, are free of toxic, allergenic, endocrine-disrupting and carcinogenic effects, do not harm microbiota and protect the shelf life of cosmetic products without harming people and the environment, in the pursuit of improving external beauty and ensuring hygiene. Another alternative we have recently encountered frequently is to restrict or even eliminate the use of preservatives by producing anhydrous formulas and to protect water resources. Our world is our common home and it is everyone's duty to take action as quickly as possible to lead a sustainable life here.     References 1. Pinto, D., Ciardiello, T., Franzoni, M. et al. Effect of commonly used cosmetic preservatives on skin resident microflora dynamics. Sci Rep 11, 8695 (2021). 2. Wang J, Liu Y, Kam WR, Li Y, Sullivan DA. Toxicity of the cosmetic preservatives parabens, phenoxyethanol and chlorphenesin on human meibomian gland epithelial cells. Exp Eye Res. 2020. 3. Panico A, Serio F, Bagordo F, Grassi T, Idolo A, DE Giorgi M, Guido M, Congedo M, DE Donno A. Skin safety and health prevention: an overview of chemicals in cosmetic products. J Prev Med Hyg. 2019 Mar 29;60(1):E50-E57. 4. Ziegler, H. The Role of Preservatives and Multifunctionals on the Oxidation of Cosmetic O/W Emulsions. Cosmetics 2022, 9, 59 5. Uludağ Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi, Cilt 7, Sayı 1, 2002 39 MARMARA DENİZİ: KİRLTİCİLER ve ÇEVRE AÇISINDAN ALINABİLECEK TEDBİRLER Yücel TAŞDEMİR* 6. Pasch, E., Voltmer, L., Gemmell, S., Walter, J. and Walton, K.L. (2009), Effects of triclosan on the normal intestinal microbiota and on susceptibility to experimental murine colitis. FASEB J, 23: 977.10-977.10. 7. Adolfsson-Erici M, Pettersson M, Parkkonen J, Sturve J. Triclosan, a commonly used bactericide found in human milk and in the aquatic environment in Sweden. Chemosphere. 2002 Mar;46(9-10):1485-9. 8. Yueh MF, Tukey RH. Triclosan: A Widespread Environmental Toxicant with Many Biological Effects. Annu Rev Pharmacol Toxicol. 2016;56:251-72. 9. Olaniyan, L.W.B., Mkwetshana, N. & Okoh, A.I. Triclosan in water, implications for human and environmental health. SpringerPlus 5, 1639 (2016). 10. Weatherly LM, Gosse JA. Triclosan exposure, transformation, and human health effects. J Toxicol Environ Health B Crit Rev. 2017;20(8):447-469. 11. Byford JR, Shaw LE, Drew MG, Pope GS, Sauer MJ, Darbre PD. 2002. Oestrogenic activity of parabens in MCF7 human breast cancer cells. The Journal of steroid biochemistry and molecular biology 80(1): 49-60. 12. Murphy B, Hoptroff M, Arnold D, Eccles R, Campbell-Lee S. In-vivo impact of common cosmetic preservative systems in full formulation on the skin microbiome. PLoS One. 2021 Jul 7;16(7):e0254172.     Dr. Tuğba Sağır Biotechnologist / R&D Manager Pim Grup